The present invention relates generally to the construction of ropes, and more particularly, to a carrier rope construction which is particularly suited for paper machine threading systems in the paper industry, in particular in paper, cardboard, tissue and pulp making machines or in paper, cardboard, tissue and pulp finishing machines. A carrier rope system is often used for threading the paper, cardboard, tissue or pulp web into and through the paper machine.
Carrier rope systems can be quite complex, utilizing multiple ropes of various sizes depending upon the machine operation. Typically, the carrier ropes twist, turn and travel up and down through the system, riding over a series of pulleys or sheaves. During operation, a carrier rope system is under constant tension and in constant contact with sheaves—a combination that leads to abrasion degradation of the carrier rope.
While the primary function of the carrier rope to grip a paper web and carry it along through the paper machine, a constant obstacle for the paper industry is improving the abrasion resistance of a carrier rope while maintaining effective grip properties of the rope.
U.S. Pat. No. 5,934,168, relates to improving the effective grip of cored braided ropes for the transfer of paper webs in paper machines. This rope sought to improve its effectiveness in gripping paper webs by forming raised portions over the rope circumference by using different multiple thread counts in the different running directions and/or the use of twisted laid fiber elements and/or the use of fibers with profiled fiber cross-sections and/or textured crimp fiber yarns.
U.S. Pat. No. 5,931,076 relates to the manufacture of large-diameter braided ropes using low elongation fibers without the need for multiple-stage twisting of the yarns. The rope is formed by the braiding of strands which themselves have been braided, as opposed to braiding twisted yarns.
What is needed therefore is a carrier rope for the threading of paper webs through paper machine systems having an improved grip and resistance to abrasion degradation.